Methods and means for treating and automatically transferring custody of petroleum



June 2, 19 J. P. WALKER ETAL 3,135,113

METHODS AND MEANS FUR TREATING AND AUTOMATICALLY TRANSFERRING CUSTODY OFPETROLEUM Filed July 13-, 1959 6 Sheets-Sheet l :"IMIL" 1 GAS OUTLETINVENTORS ATTORNEY June 2, 1 64 J. P. WALKER ETAL METHODS AND MEANS FORTREATING AND AUTOMATICALLY TRANSFERRING CUSTODY OF PETROLEUM 6Sheets-Sheet 2 Filed July 15, 1959 QQWWMQQQQU QQSQ INVENTORS JAY RWALKEIZ BY ROBERT A. HODGSON flfl M ATTORNEY IN V EN TORS JAY I? WA L KE 12 A TTORNEY 3,l35,l 13 OR TREATING AND AUTOMATICALLY 6 Sheets-SheetI5 ROBERTAHODGS N aflq 76 44! khbvikw J P. WALKER ETAL EANS FTRANSFERRING CUSTODY OF PETROLEUM METHODS AND M mash NUSWWMQQ NQQ June2, 1964 Filed July 15, 1959 J. P. WALKER ETAL June 2, 1964 3,135,113METHODS AND MEANS FOR TREATING AND AUTOMATICALLY TRANSFERRING CUSTODY OFPETROLEUM Filed July 13, 1959 6 Sheets-Sheet 4 Y MH km: SE

kmsvixw QQRD m INVENTORS JAY R WALKER ROBERT A. H006 'BYZ ATTORNEYQQMQWQQQQU INVENTORS JAY P WALKER A T TORNEY June 2, 1964 J. P. WALKERETAL 3,135,113

METHODS AND MEANS FOR TREATING AND AUTOMATICALLY TRANSFERRING CUSTODY OFPETROLEUM 6 Sheets-Sheet 6 Filed July 13, 1959 LEASE M4LVE IN VEN TORSJA Y 2 WA L K E Q POBEIZT A. HODGSON am- BY {4w ATTORNEY the percentbasic sediment and water in the oil.

United States Patent "ice 3,135,113 'METHODS AND MEANS FOR TREATENG ANDAUTQMATICALLY TRANSFERRENG CUSTGDY "0F TETRQLEUM Jay 1. Walker andRobert A. Hodgson, Tulsa, @kian, as-

signers to National Tank Company, Tulsa, Okla, a corporation of NevadaFiled July 13, 1959, Ser. No. 826,556 Claims. (Cl. 73-200) The presentinvention relates to treating crude petroleum and transferring the oilproduced to a point of sale.

More specifically, the invention'relates to a combination of treatingapparatus for crude petroleum and means for measuring the clean oilproduced and conserving liquefiable hydrocarbons evolved as vapors andinsuring the clean oil produced is of desired quality.

It has been customary to treat crude petroleum on a lease and store theclean oil produced by the process in run tanks. Periodically, thepurchaser of the oil tests If the oil is of merchantable quality, havingonly a basic sediment and water percent in the order of .1 to .5, thetank is measured and emptied into a pipe line controlled by thepurchaser. Oil has been produced, sold, and its custody transferred, inthis manner for many years.

Several systems have been adopted to make some, or all, of theconventional procedures, presently in use, automatic to reduce themanpower required, maintain the quality standards of the oiltransferred, conserve the quantity and gravity of the liquid oiltransferred, and increase the accuracy of the measurement of the oiltransferred. ,The present invention is directed to accomplishing all ofthese results with one unitized combination of apparatus.

A primary object of the present invention is to treat ,crude petroleumand measure the clean oil produced while recovering evolved vapors fromthe clean oil.

Another object is to prevent the measuring of treated oil byrecirculating the oil through the treating process if the treated oil tobe metered falls below a specified quality.

Another object is to maintain the bottom of a storage vessel for cleanoil free of bottom sediment and water.

Another object is to shut in well production to the treating process ittreated oil is not being metered and transferred at least as fast as thetreated oil is produced.

The present invention contemplates a treater, a storagesurge vessel andmeter combination. The relatively hot, treated, oil product of thetreater weathers, or evolves, vapors above its surface, in thestorage-surge vessel, the vapors containing, hydrocarbons which can beliquefied at storable conditions. These vapors are reduced intemperature in order that the liquefiable hydrocarbons may be recoveredand returned to the liquid metered.

The present invention further contemplates the evolved vaporsabove thesurface of the relatively hot treated oil in the storage-surge vesselbeing withdrawn for liquefaction when thepressure of the vapors reachesa predetermined value.

The invention further contemplates the vapors being reduced intemperature by heat exchange with a cooler fluid.

The present invention contemplates a treater, storagesurge vessel andmeter combination in which hydrocarbon vapors are evolved in thestorage-surge vessel above the treated oil and the cooler portions ofthe oil from the storage-surge vessel are used as a liquid piston in acompressor, or pump, to absorb, condense and compress the vapors; themixture been returned to the treater to recover the liquefiablecomponents of the vapors.

The invention further contemplates the vapors being 3,l35,ll3 PatentedJune 2, F364 reduced in temperature by both a heat exchanger and aliquid, cooler than the vapors, which liquid is used as a piston toabsorb, condense and compress the vapors.

The invention also contemplates a treater-storagevessel-rnetercombination in which a pump is used to continually draw oil treated oilfrom the bottom of the storage oil and recirculate the oil through thetreater. The bottom portion of the oil in the storage is generally coolenough to be used as an eflicient liquid piston in a compressor toabsorb, condense and compress the vapors evolved above the treated oilin the storage-surge vessel when the pressure of the evolved vaporsreaches a predetermined value.

The invention also contemplates a treater-storage-vessel-metercombination in which the bottom sediment and water in the treated oil instorage is detected and used to control recirculation of the treated oilfrom the storage vessel to the treater when the percent of bottomsediment and water in the treated oil reaches a predetermined value.

The invention further contemplates means for detecting when the treatedoil in the storage tank increases to a pre determined maximum amount andprovision to interrupt the flow of production from the well to thetreater until the storage tank quantity reduces below the maximumamount.

Other objects, advantages and features of this invention will becomeapparent to one skilled in the art upon consideration of the writtenspecification, appended claims, and attached drawings wherein;

FIG. 1 is a diagrammatic illustration of a combination of a treater,surge tank and metering vessel as a part of the system in which theinvention is embodied;

FIG. 2 is a diagrammatic illustration of the control system for thecombination of FIG. 1 as positioned to till the meter tank;

FIG. 3 is a diagrammatic illustration of the control system of FIG. 2 aspositioned to empty the meter tank;

FIG. 4 is a diagrammatic illustration of the control system aspositioned to interrupt the metering when the level in the surge tank isat a predetermined minimum;

FIG. 5 is a diagrammatic illustration of the control system aspositioned to interrupt the metering when the quality of the oil in thesurge tank is not merchantable; and

FIG. 6 is a diagrammatic illustration of another form of surge tank andmetering vessel with a pipe line surge tank.

Referring to FIG. 1, there is illustrated a combination of oil wellemulsion treater 1, metering tank 2 and surge tank 3 which, togetherwith its control system embodies the present invention. The broadfunction of the combination is to receive oil and emulsion into treater1 and continually produce a merchantable product into surge tank 3 whichmay then be metered to a purchaser. Properly controlled, thiscombination of treater, surge tank, metering tank and control system isa novel form of lease automatic custody transfer unit.

Treater 1 is illustrated in vertical tank form. However, this form isnot to be taken as a limitation for a treater to function in thiscombination. The treater could be horizontal, or the process could becarried out in a plurality of vessels. The specific form of treaterillustrated forms the subject matter of Walker et al. SN 806, 000, filedApril 13, 1959, now Patent 3,043,072.

Treater 1 is basically identified by elongated, cylindrical tank 5,extending vertically, its upper end closed by a domed head 6 and itslower end closed by a dished bottom 7. The tank is set on a suitablesupport 8 and has an internal, transverse, horizontal partition 9 nearits upper end. This transverse partition 9 forms, with head 6, a gasseparation chamber ltl.

Also internal of the vessel-tank 5 and near its bottom is mounted arelatively small, separate, removable, shell 10A. Actually, shell 10Acharacterizes a small, horizontal, separator into which a well stream tobe processed is introduced through inlet 11. The gaseous phase of thewell stream introduced into separator 10A is removed through conduit 12.The liquid phase is removed through conduit 13. Conduit 13 is valvedwithin separator 10A by a float on the liquid level therein.

Separator 10A is mounted so that it may be removed from the shell as aunit. This arrangement facilitates cleaning and servicing the separatorand replacing it with one having a difierent pressure capacity. Liquidconduit 13 is extended upward, from separator A, through heat exchanger14.

Although not illustrated in FIG. 1, separator 10A is normally expectedto be part of a complete system for staging the pressure reduction ofthe well stream from the well head to the treating process Within tank5. Several pressure ranges could be recited to illustrate the relationbetween the structures. However, these ranges would be relative,depending upon subjective characteristics of the well stream and theequipment available to process the well stream. It must also beunderstood that treater 1 may have a much simpler pressure system thanillustrated. The treater 1, as far as the present combination isconcerned, is only one of many possible forms of a source ofmerchantable oil to be transmitted to surge tank 3 for metering by meter2.

To continue tracing the flow of well fluids through the treater, heatexchanger 14 is seen to be composed of essentially, three tubestelescoped Within each other concentrically. Liquid conduit 13 isarranged as the inner tube. Arranged concentrically about conduit 13 isconduit 15 which removes liquid from the separation charnber 1tdownwardly through heat exchanger 14. The liquids removed from separator10 by conduit 15, are taken to a heat treating process in the lowerpar-t of tank 1 and just above the location of separator 19A. Arrangedconcentrically about both conduit 13 and conduit 15 is conduit 16.Downcorner conduit 16 removes the clean, merchantable oil produced bythe heat treating process within tank 5 and heat exchanges it with thewell stream of conduit 15 to conserve heat introduced into the heattreating process.

Conduit 13 is extended out of the top of the other conduits 15 and 15 ofheat exchanger 14 to connect with heat exchanger 17. Heat exchanger 17is made up of three concentric tubes. Tube 18 constitutes the outershell of heat exchanger 1'7 and receives conduit 13 at its lower end.Conduit 19 is connected to the upper end of tube 18 and to a diverterplate mounted on the inner wall of chamber 10. This particulararrangement of tube 18, as the external shell heat exchanger 17,provides heat exchange between the incoming well stream and all thegaseous products developed in the subsequent heat-treating of this samewell stream within shell 1. The liquids of conduit 13 are thus passed upthrough heat exchanger 17 and diverted upon the walls of the upper partof the shell of the tank 5 in chamber 10. A portion of the gas of thewell stream is separated from the well stream by this action and carriedout of the tank 1 through a mist extractor structure 20 and outletconductor 21;

Within external tube 18 a tube 22 is concentrically telescoped withinthe third tube in order that all gas evolved in the treatment of theliquid well stream will be brought into indirect contact with the wellliquids before these liquids are heat-treated. Specifically, tube 22extends downwardly from heat exchanger 17, through transverse partition9, to a point Well below the surface of the clean oil produced by theprocess.

Telescoped up inside of tube 22 is another tube 23 which brings thegases evolved directly from heat treating up into exchanger 17. Holesare provided in the Wall of tube 22, just below partition 9, to bringgaseous vapors developed above the surface of the clean oil up into theseparation chamber 10.

Just below the heat exchanger 17, connected to tube conduit 22, is aconduit 24. Conduit 24 takes all of the uncondensed vapor, from bothconduits 22 and 23, into heat exchange with the well stream liquidswhich have collected on the bottom of chamber 19. After this heatexchange, the gasses which still are not condensed are ejected into thegaseous phase of chamber 10, passing out mist extractor 20 and gasconduit 21.

Attention is now redirected to the well stream liquids collected on thebottom of chamber 10 and which flow down conduit 15. The liquids inconduit 15 are introduced into a heating zone 25 in the lower portion ofvessel 1, directly above separator 10A. A firetube 26 is the source ofheat for zone 25.

Heating zone 25 is formed about firetube 26 by a hood 27, baffle 28 andthe sides of tank 5. Hood 27 has a depending skirt, or lip, closelypositioned to vertical bafiie 23. Bathe 28 is extended well belowfiretube 26 in order to form the heating zone 25 about firetube 26 whichwill contain only emulsified oil and water to be directly heated byfiretube 26. The emulsion is broken by the heat in Zone 25 and separatedinto oil and water. A coalescing section above the heating zonecompletes the separation of the oil and water. The function of thesestructural elements within treater 1, to produce a clean oil product oflow water content, is adequately explained in co-pending Walker et al.SN 806,000. This clean oil product is withdrawn from shell 5 into heatexchanger 14 and conducted to surge chamber 3 by conduit 29.

METERING TANK Z-SURGE TANK 3 Surge tank 3 is an intermediate depositoryof the clean oil product of treater 1, between the producer and thepurchaser to whom the oil is metered. This intermediate depository,represented by surge tank 3, provides several salient features of theinventive combination herein disclosed.

Both surge tank 3 and metering tank 2 are illustrated as a unit.Metering tank 2 is mounted beneath surge tank 3 so that oil to bemetered may flow from tank 3 into tank 2 by gravity. A base isillustrated at 40 for direct sup port of metering tank 2. Intermediatesupport 41 is illustrated between metering tank 2 and surge tank 3.

Surge tank 3 is shown in the form of a vertically elongated tank havingdished head 42 and dished bottom 43. Conduit 29 enters the side of tank3 and the clean oil product from treater 1 is flowed into a verticallyelongated pipe extension 4-4. Oil is withdrawn from tank 3, formetering, through pipe 45. Fill valve 46, in pipe 45, is opened to beginthe filling operation of metering tank 2, connected to the lower end ofpipe 45.

Metering tank 2 is illustrated as the same general type of verticallyelongated tank as is surge tank 3, having dished head 47 and dishedbottom 48. Oil flows into meter tank 2 through pipe and is delivered toa point of sfle by conduit 49. Dump valve 50 controls the delivery ofmetered oil by conduit 49. It can be appreciated that the measuredvolume of tank 2, between dump valve 50 'and fill valve 46 constitutesthe unit which with clean oil is metered and delivered from the well toa point of sale.

Part of the invention lies in the system controlling fill valve 45 anddump valve 50. Some of the control impulses for these valves aregenerated by lower float and upper float 56. Lower float 55 is locatedin a chamber-enlargement of conduit 49. Upper float 56 is located in thechamber-enlargement of conduit 57. Conduit 57 extends from dished head47, up through dished bottom 43 of surge tank 3, to the vapor spacebeneath the dished head 42.

Other impulses of the control system in which the invention is embodiedare generated by top level float 58 and bottom level float 59 in surgetank 3. The level of clean oil product in surgetank 3 is normallycontrolled between the levels established by floats 58 and 59.

A bad-oil drawoff conduit 60 communicates with the lower strata ofliquids in surge tank 3, through dished bottom 43. Ba -oil valve 61 isestablished in conduit 60 to control the amount of non-merchantable oilwithdrawn fuom surge tank 3 through conduit 60. A vapor drawofl conduit62 is also extended through the side of surge tank 3 to communicate withthe vapor space below dished head 42. Vapor valve 63 is established inconduit 62 to control the withdrawal of vapor from the top of tank 3through conduit 62.

Both conduits 60 and 62 are illustrated as branches of conduit 64.Conduit 64 removes both this liquid and vapor to compressor 65 whichutilizes the liquid as a piston to compress, condense and absorb thevapor. The liquid and compressed vapor product of compressor 65 isdelivered to conduit 66 for introduction into conduit 11 andrecirculation through the treating system.

-ment to the vapor pressure in the top of tank 3 so a fluid pressure maybe established in accordance with the vapor pressure. The plan is forthis vapor pressure to increase to a value which will establish acontrol action in the system with the fluid pressure.

In general, the control system in which the invention is embodied, hascontrol actions established on it with surge tank floats 58 and 59,meter tank floats 55 and 56, bottom sediment and water monitor 67,pressure regulator 68 and time-cycle controller 70. Time-cyclecontroller 70 is not illustrated in FIG. 1. The control system thenregulates fill and dump valves 46 and 50, lease valve 69, bad-oil valve61, vapor valve 63 and motor-compressor 65 to carry out objectives ofthe invention.

NORMAL METERINGFIG. 1

It is contemplated that, normally, the well stream will be supplied totreater 1 and processed into a clean oil product which will beacceptable for sale on the market. This merchantable oil will beproduced from treater 1 into surge tank 3. The clean oil will then bewithdrawn r from surge tank 3 into metering tank 2 to form a series ofincrements which are integrated as the total volume of oil passed to aconsumer. It is intended that the increments be withdrawn at a ratewhich will keep the level of oil in surge tank 3 between floats 58 and59.

Lease valve 69 will be open, and clean oil will flow into surge tank 3through conduit 29. Fill valve 46 will then be opened, while dump valve50 is kept closed, to fill meter tank 2 until float 56 is actuated toclose fill valve 46 and open dump valve 50. The fall of float 55 willindicate meter tank 2 has been emptied and valve 50 will close and fillvalve 46 will open. The number of meter -tank 2 dumps will be integratedby a simple counting mechanism to give the total amount of clean oildelivered to a consumer in sale.

DEPARTURE FROM NORMAL METERING AND OPERATION from conditionspredetermined as normal. The normal 6 metering will then be interruptedfor the period necessary to return the oil to acceptable standards,

The level of oilin surge tank 3 may lower to float 59 because of someslowing, or interruption, of the flow through conduit 29. Tank 3 againbecomes a convenient means of determining this departure from conditionspredetermined as normal. The normal metering will then be interruptedfor the period necessary to return the level to the top float 58.

The level of oil in surge tank 3 may rise to upper float 58 because ofhigh production output of treater 1 into tank 3. The lease productionmay then be shut in until the metering function lowers the level in tank3 below float 58.

The vapor pressure in the top of tank 3, beneath head 42, may increaseto a value approaching that maintained on the treater 1. This willthreaten to stop the flow through conduit 29, from treater 1. Pressureregulator 68 will monitor this vapor pressure and start the controlaction which will draw off vapor and oil from the bottom of tank 3 toreturn the pressure to predetermined limits. At the same time, theliquefiable components of the vapor are conserved, returned to the oilof tank 3, to conserve both the gravity and quantity of the oil to bemetered. It is not to be overlooked that the heat exchange betweenatmosphere and head 42 can also be depended upon to condense vapors onthe top of the oil in the tank 3, returning the condensate to the oil tomaintain its quantity and gravity.

Time-cycle controller 70, not shown in FIG. 1, may also be used toperiodically draw vapors and oil from the bottom of tank 3 intotreater 1. In this re-cycling there is the insurance against thebuild-up of bottom sediment and water in the bottom of tank 3 underpredetermined conditions. Should these conditions be exceeded, themonitor 67 or regulator 68 will keep the compressor going to keep thevapor pressure and bottom sediment and water of tank 3 under control.

It can now be appreciated that surge tank 3, with treater 1 and meteringtank 2 performs several general and specific functions to insure thatmerchantable oil is delivered to a consumer from the well at a ratecompatible with the operation of the treater 1 and metering systemincluding tank 2.

THE CONTROL SYSTEM In FIG. 1 only the devices responsive to variables,and

the valves controlled by the impulses established by the FILLING OFMETER TANK 2 It must be clearly understood that the elements of thecontrol system as illustrated in FIG. 2 are shown in the .positions theyhave following the level of oil to be metered in surge tank 3 havingreached float 58, actuated the float 58, established a fluid controlpressure and thereby closed lease valve 69 and supplied fluid pressurepower to open fill valve 46. The positions of the elements are shownjust after the level in tank 3 has lowered by reason of draw-oil intotank 2 to cause float 58 to lower enough to permit lease valve 69 toopen.

Float 58 is illustrated diagrammatically as actuating a three-way valve80. Valve is representative of all similar valves illustrated throughoutthe drawings. Valve 80 is shown as supplied a fluid pressure which isestablished in conduit 81 when float 58 is raised by the level oftreated oil in surge tank 3. The fluid pressure in conduit 81 is alsoestablished in conduit 82 and imposed upon the top of spring-openinglease valve 69. A valve suitable for the service performed by valve 80,and all simi- 7 lar valves in the disclosure, is disclosed in the patentto Swatsworth 2,860,660.

Pipe 83 is also connected to pipe 81 as a branch and is the means bywhich the fluid pressure generated by float 58 is used to shiftpiston-operated valve 84. Valve 84 has its own fluid pressure supplywhich is applied to pipe 85 when the fluid pressure of pipe 83 isapplied to valve 84. In FIG. 1, pipes 81, 82 and 83 are at atmosphericpressure, valve 80 having been actuated by float 58 to connect pipe 81to atmosphere.

Pipe 85 is branched to simultaneously supply fill pilot valve 86 anddump pilot valve 87. Both valve 86'and valve 87 are three-Way valves,similar to valve 80, and mechanically actuated between their alternatepositions by cams. As illustrated in FIG. 2, fill pilot valve 86establishes the fluid pressure of pipe 85 on fill valve 46 to open it.The fact that the output of valve 86 interlocks with control signalsdeveloped by float 59, detector 67 and the position of dump valve 50 ispresently incidental to the fact that fill valve 46 is actuated to beginfilling meter tank 2 with clean merchantable oil from surge tank 3.

As heretofore indicated, FIG. 2 illustrates the control system at thatpoint in its cycle of operation at which pilot valve 86 passes the fluidpressure of pipe 85 to open valve 46. Pilot valve 86 was positioned forthis function by cam 88. Cam 88 was positioned through gear-linkage withpiston 89. Piston 89 is spring-loaded to return to the positionillustrated in FIG. 2 and moved to its alternate position when a fluidpressure impulse is applied to it. The gearing between piston 89 and theshaft of cam 88 and the cam 90 is of the rachet type whereby each fluidpressure impulse which moves piston 89 advances the cams in onedirection only. The cams are cut and spaced on their shaft so they willalternately open and close valves 86 and 87 as they are advanced witheach fluid pressure impulse.

In FIG. 2, float 55 is assumed to have signaled the completion ofdumping from meter tank 2 by establishing a fluid pressure impulse inconduit 91. The fluid pressure impulse in pipe 91 has been appliedthrough doublecheck valve 92 to position piston 89 so cam 88 will openvalve 86 and cam 90 will close valve 87. As float 55 is raised by liquidfilling meter tank 3, it actuates its threeway pilot valve and reducesthe pressure in pipe 91 to atmosphere, no change takes place in theposition of double-check valve 92, piston 89 or cams 88 and 90. This,then, is the portion of the cycle FIG. 2 represents. Meter tank 2 isfilling, no impulse is applied to piston 89, and the next normalsequence will be the raising of float 56 to establish a fluid pressurein pipe 93. The fluid pressure established in pipe 93 will then shiftdouble-check valve 92 to its alternate position, actuate piston 89 toactuate cams 88 and 90 and close fill pilot valve 86 and open dump pilotvalve 87.

DUMPING OF METER TANK 2 The actuation of valve 46 and valve 50,alternately, continues without interruption as long as the level ofmerchantable oil in surge tank 3 remains between the predeterminedlimits established by the position of floats 58 and 59. FIG. 3 shows thealternate position of pilot valves 86 and 87. The fluid pressure impulseof pipe 85 is applied to the underside of the diaphragm of valve 50 toopen valve 58. Note may now be made that the valves 50 and 56 areinterlocked with each other by having their opening impulses routedthrough a three-way valve mounted on each valve to insure that when onevalve is open the other is closed.

The raising of float 56, as shown in FIG. 3 starts the dumping functionof the cycle. The depression of springloaded piston 89 is indicated, bythe fluid pressure output of the three-way valve actuated by float 56.The piston will return to its up position when float 56 lowers as thedumping proceeds, leaving pilot valves 86 and 87 as shown.

Dump pilot valve 87 now passes the fluid pressure of pipe to theunderside of dump valve 50. With dump valve 50 open, meter tank 3empties to the consumer through conduit 49. At the time the output ofpilot valve 87 is applied to valve 50, the output is also applied toblocking valve 97 by means of pipe 98.

Although the blocking valve 95 no longer prevents an impulse from float59 being applied to shuttle valve 84, blocking valve 97 now takes overthis function during the dumping period. If float 59 signals the surgetank level is low, it will not eifect the filling-dumping function ofthe control system until both pipes 98 and 94 are at atmosphericpressure.

It is best if a low-supply signal from float 59 be applied to interruptthe metering function after the dumping, and before filling, of metertank 3. Then oil will not be left standing in the tank 2 to depositparaffin, etc. on the tank 2 walls.

LOW LEVEL IN SURGE TANK 3 FIG. 4 is used to illustrate precisely whathappens in the system when the level of measurable oil in tank 3 is solow as to necessitate shutdown of the metering. Both floats 55 and 56are down. Float 55 calls for fill pilot valve 86 to pass the pressure ofpipe 85 to fill valve 46 to open it. If this valve 86 pressure werepassed immedi ately blocking valve 95 would take over the job ofpreventing the pressure of pipe 96 from passing to shift valve 84.However, valve 180 slows the development of valve 86 pressure on thepipe to valve 46 long enough to keep blocking valve 95 in the positionshown in FIG. 4 so valve 84 will be shifted by the pressure output ofpipe 96 and reduce the pressure of pipe 85 to atmosphere.

Valve 100 in this system is of the type that passes the pilot valve 86output at a controlled rate, but relieves the pressure past it, to fillvalve 46, with substantially no restriction. Study of the cycle ofoperation will show that the actuating pressure on valve 46 must beremoved quickly, and that the exhaust through pilot valve 86 is the onlyprovision shown as available. Access to this bleed through valve 86 mustbe made by having a minimum restriction through valve 1% toward valve86. Of course, an extra valve could be employed directly in the pipe tovalve 46 which would be sensitive to a pressure decrease of apredetermined amount to quickly relieve the actuating pressure. In thepresent disclosure, it is simpler to regard valve 100 as having thediflerential desired between its two bleed rates.

When supply pressure to both pilot valves 86 and 87 is removed, the dumpand fill valves 46 and 50 remain closed until float 58 raises,indicating a full surge tank 3 of fluid to be metered is available.Shift valve 84 will then be positioned to pressure pipe 85 and themetering will continue by fill valve 46 being opened. The systemoperation will then shift to that portion of its cycle represented byFIG. 2 in which meter tank 2 is filling.

RECIRCULATION OF BAD OIL FROM TANK 3 By Monitor 67 FIG. 5 is establishedto illustrate how the bottom sediment and water monitor 67 controls thesystem to recirculate the oil from the bottom of surge tank 3. Thecontrol action by monitor 67 is taken at any time the monitor detectsthe need. However, the system is illustrated to show the meteringfunction as not interrupted during a filling cycle of meter tank 2. Thisprovision recognizes the desirability of reducing the standing time ofoil in meter tank 2 to a minimum. The reduced standing time militatesagainst paraflin, etc. fouling the walls of the tank with a layer ofsolids which will make the metering progressively inaccurate.

Monitor 67 is shown specifically establishing an electric signal outputon solenoid-operated fluid pressure valve passes the control fluidpressure'from pilot valve 86.

101. Valve 101 establishes a control fluid pressure in pipe 102. Thefluid pressure is applied to blocking valve 103 if fill valve 46 isopened by the control fluid pressure of pilot valve 86. However,blocking valve 103 normally If this control pressure is passed to fillvalve 46 to place the meter tank 2 on its filling cycle, the controlpressure is also placed on blocking valve 104. Blocking valve 104 isplaced in pipe 102 and when energized by the control pressure passed byblocking valve 103, isolates the output of monitor solenoid valve101frorn blocking valve 103.

Thus, when fill valve 46 is opened, the monitor 67 cannot stop thefilling operation. Only after the fill-dump system for -meter tank-2 hasgone into its dumping cycle can the monitor 67 signal halt the meteringoperation.

However, the monitor .67 does start the immediate recirculation of thebad oil it detects in surge tank 3. Pipe 105 branches from pipe 102 andtheoutput of valve 101 shuttles double check valve 106 and double checkvalve 107 to energize fluid pressure operated electric switch 108.Switch 108 is essentially a transducer of the control fluid pressure inpipe 109 into the electrical power applied to the motor 110. Motor 110powers compressor 65. Compressor 65 takes the bad oil of conduit 60 andthe vapor of conduit 62 and uses the oil as a liquid piston to compress,absorb and condense the vapor of conduit 62.

The resulting mixture of liquid and vapor is introduced intotreater :1through conduit 11. A compressor suitable for this service ismanufactured by Nash Engineering Company, SouthNorwalk, Connecticut, asType MD.

To make the bad oil of conduit 60 and the vapor of conduit 62 availableto compressor 65 at the time motor 110 actuates compressor-6'5, pipe 111branches from pipe 109 to open valves 61 and 63. The control fluidpressure developed by bottom sediment and water solenoid valve 101 is,therefore, used directly to open valves 61 and 63 and transduced toelectric power to drive compressor65.

By Time-Cycle Controller 70 "The concepts of the control systemencompass a high degree of flexibility. Bottom sediment and watermonitor 67 may be regarded as a sentinel, taking the proper controlactionto eliminate bad oil at a certain level of concentration, wheneverit appears. However, an anticipatory, or'preventive, measure is alsoavailable. The oil from the bottom of surge tank 3 can be recirculatedon a trol fluid pressure in pipe 113. The pressure in pipe 113 shuttlesthe double check valves 106 and 107 to start compressor 65 and openvalves161 and 63.

By Vapor Pressure Regulator 68 Recovery of the hydrocarbon components ofthe vapor evolved above the oil in surge tank 3 can be very important.Condensation may occur on head 42 if the ambient temperature is coolerthan the vapors. A cooler fluid can be used to heat exchange with thevapors evolved.

FIG. 1 illustrates how these vapors can be drawn off with conduit 62 andcompressed, condensed and absorbed by the cooler fluid from the bottomof tank 3. This recovery step is taken every time monitor 67 orcontroller 70 recirculates bad oil. On the other hand, the system isshown asso flexible that the pressure of the vapors can start this typeof recovery.

Regulator 68'is disclosed as responsive to the vapor pressurebeneathhead '42. When the vapor pressure reaches a predetermined value, theregulator 68 develops a control fluid pressure in pipe 113. The controlpressure in pipe 114 shuttles double check valve 107 to take overcontrol of compressor 65 and open valves 61'and 63 just as controller 70and monitor 67 did.

SUMMATION The foregoing disclosure has been limited to certain structureto keep from obscuring the features of automatically metering available,merchantable, oil from surge tank 3, keeping the bottom of tank 3 cleanand recovering vapor from the top of the oil in tank 3. The cooling ofthe vapors evolved above the tank 3 oil, to condense these vapors, canbe done in a number of ways. FIG. 6 illustrates one way which has beenheretofore indicated. Other functions of a custody transfer unit, suchas sampling, integrating, limiting the metering to an allowable amountand providing a pipe line surge, are also shown in FIG. 6.

Cooling FIG. 6 shows the surge tank 3 mounted on top of the meter tank2. This unit is further shown mounted on top of a pipe line surge tank120. Part of the control system of FIGS. 2-5 is shown connected tofloats 58 and 59 in surge tank 3 and floats 55 and 56 in meter tank 2.

FIG. 6 shows a cooling coil 121 mounted in the top of surge tank 3. Thecooling coil 121 is not shown attached to a source of fluid. However, itis intended that a fluid, cooler than the evolved vapors on the top ofthe oil in tank 3, be forced through coil 121 to provide a cool surfaceon which hydrocarbons will condense from the vapors so they will berecovered into the tank 3 as merchantable oil to be metered.

Of course, there are other forms of heat exchangers for the vapors intank 3. Coil 121 is intended to merely represent one of the manypossible means with which heat exchange is used to lower the temperatureof the vapors, condense them and recover them as liquids. The use of acooler liquid in a compressor, to recover the vapors by recirculationthrough the treating process, was illustrated in FIG. 1. The coolingcoil 121 can complement the compressor, or under some conditions ofoperation, substitute for the compressor, in this process.

Counting-Jnregrating-A llowable The portion of the control systemdisclosed in FIG. 6 can'be compared to that of FIGS. 25. The pipe 91from float55 is noted as being pressured each time a dump of: meter tank2 is completed. This impulse can be used to actuate a counting, orintegrating, mechanism to indicate and/or record the total amount of oilpassed through themeter.

A pipe 122 is branched from pipe 91 to apply the fluid pressure impulsegenerated by float 55 to a diaphragm operator 123. Operator 123 ismechanically linked to a counter, or totalizer, 124 which cumulates thenumber of tank 2 units dumped. Although not shown, compensation of thecounter, is easily provided from temperature of the oil measured.

An allowable counter 126 is also indicated as driven by operator 123.Counter 125 is designed to establish a control fluid pressure in pipe126 after a predetermined amount of oil has been metered through tank 2.The control pressure in pipe 126 is then applied to pipe 96. Therefore,when passed by blocking valves 97 and 95, the allowable counter impulseshifts valve 84 and shuts down the metering and custody transferoperation. The surge tank 3 will fill and shut in the lease with valve69.

Sampling It is generally desired that a sample be taken of each unit oftank '2 oil. A sampling mechanism 127 is shown mounted on the top oftank 2. This sampler could take the form of that disclosed in the. PittsPatent 2,872,817.

The actuation of the sampling system, and its details, has not beenshown. The system may be quite important to a complete custody transferunit, but its illustration in FIG. 6 has been held to the simplicitywhich will enable clarity.

the embodiments of the invention to be illustrated with Pipe Line SurgeThe tank 120 on which the surge tank-meter tank unit is mounted isdesirable to provide a regular, consistent, delivery to the pipe line ofthe purchaser of the oil. Floats 128 and 129 can control the amount ofoil held in this reservoir. A control system, not illustrated in FIG. 6,can control motor 130 to pump the metered oil into a pipe line, throughconduit 131. The intended operation is that, with tank 120 as areservoir between the meter 2 and the pipe line, delivery will berelatively steady and uninterrupted during the allowable period ofproduction.

From the foregoing it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forth,together with other advantages which are obvious and which are inherentto the method and apparatus.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of theclaims.

As many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying drawings is to beinterpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

l. The method of treating and transferring crude petroleum, including,

heating the crude to break any emulsion of oil and water in the crude,

removing and collecting clean oil remote from the heating step,

measuring the collected clean oil and delivering the clean oil to apoint of use,

removing vapor evolved from the clean oil collected,

removing clean oil from a relatively cool section of the clean oilcollected,

utilizing the relatively cool clean oil to condense and absorb andcompress the vapor evolved from the clean oil collected,

and mixing the relatively cool clean oil and condensed and absorbed andcompressed evolved vapors with the crude petroleum which is heated tobreak any emulsion of oil and water in the crude,

whereby the evolved vapors are restabilized.

2. A system for treating and transferring crude petroleum, including,

a shell,

means for bringing the crude to the shell for treatment,

a heat means in the shell arranged to heat the crude until any emulsionof oil and water in the crude is broken,

a coalescing means within said shell for agglomerating the clean oilinto a product for transfer and water into a body for disposal,

a collecting vessel connected to the coalescing means of the shell,

means for transferring the clean oil to the collecting vessel from thecoalescence means,

a measuring means for receiving the clean oil of the collecting vesselto measure and transfer the clean oil to a point of use,

a first conduit means for removing evolved vapors from above the cleanoil in the collecting vessel,

a second conduitmeans for removing cool clean oil from the collectingvessel,

a compressor employing the oil of the second conduit means to condenseand absorb and compress the vapors of the first conduit means,

and a third conduit means for transferring and mixing the mixture ofvapors and oil of the compressor with 12 the crude petroleum which isheated, whereby the evolved vapors are restabilized. 3. The method oftreating crude oil and changing custody of the clean oil produced,including,

'5 heating the crude oil to break any emulsion of oil and water in thecrude,

agglomerating the clean oil and water into separate collections,

removing the collected oil to a point remote from the treating processand holding the collected oil under a pressure less than the pressureunder which the crude was treated,

removing measured quantities of oil from the clean oil collected anddepositing the measured quantities at a point of use,

removing vapors evolved from above the clean oil collected when thepressure of the vapors exceeds a predetermined value,

removing oil from a relatively cool section of the clean oil collected,

mixing the oil withdrawn from the relatively cool section and vaporsevolved from above the clean oil collected to condense and absorb andcompress the vapors,

and introducing the mixture of condensate and absorbed vapors andcompressed vapors and relatively cool oil into the crude oil to beheated, whereby the liquefiable portions of the vapors are recovered asliquids.

4. A system for treating crude oil and changing custody of the clean oilproduced, including,

a treating vessel,

means for bringing the crude to the vessel for treatment,

a heat means in the vessel arranged to heat the crude until any emulsionof oil and water in the crude is broken,

a coalescing means within said vessel for agglomerating the clean oilinto a body for transfer and the water into a separate body fordisposal,

a tank located separately from the treating vessel and connected to thecoalescing means of the treating vessel for receiving the clean oil bodyproduced by the treating vessel under a pressure less than the pressurein the treating vessel,

a measuring means connected to the tank for registering the quantity ofthe clean oil as it flows from the body of clean oil in the tank intothe custody of a purchaser,

means for transferring the clean oil body to the tank from thecoalescing means,

means for detecting the pressure of the vapors evolved from the cleanoil body in the tank and removing these vapors when their pressureexceeds a predetermined value,

means for removing oil from the body of clean oil in the tank at a pointsubstantially below the top of the tank and mixing the oil withdrawnwith the evolved vapors to condense and absorb and compress the evolvedvapors,

and means for mixing the mixture of withdrawn oil and condensate andvapors with the crude oil to be heated for recovery and conservation ofthe liquefiable portions of the vapors.

5. A system for treating and transferring crude petroleum, including,

means employing heat to reduce crude petroleum produced from an oil wellinto clean oil and water,

a collecting vessel connected to the means employing 70 heat to receivethe clean oil,

a compressor connected to the upper portion of the collecting vessel toremove vapors evolved from the surface of the clean oil and employ aliquid cooler than the vapors to condense and absorb and compress thevapors,

TJL.

a first valve in the connection between the upper portion of thecollecting vessel and the compressor,

"a second valve arranged'to control the cool liquid to the compressor,

means for detecting the pressure of the vapors in the upper portion ofthe collecting vessel,

a control system between the pressure detector and the compressor andthe first and second valves, whereby the-compressor is started and thevalves are opened when the pressure of the vapors exceeds apredetermined value,

a conduit connected to the compressor output with which the vapor andoil of the compressor output is mixed with the crude petroleum receivedby the means employingheat,

and a measuring means connected to the lower portion of the collectingvessel receiving the clean oil and measuring and transferring the cleanoilto a point of use.

6. A system for treating and transferring crude petroleum, including,

-means employing heat to reduce crude petroleum produced from an oilwell into clean oil and water,

a collecting vessel connected to the means employing heat to receive theclean oil,

a compressor connected to the upper portion of the collecting vessel toremove vapors evolved from the surface of the clean oil and employ cleanoil cooler than the vapors to condense and absorb and compress thevapors,

a first valve in the connection between the upper portion of thecollecting vessel and the compressor,

a second valve arranged to control the cool oil to the compressor,

means for detecting the pressure of the vapors in the upper portion ofthe collecting vessel,

a detector-controller connected to the lower portion of the collectingvessel and responding to the percent basic sediment and water in the oilreceived into the vessel,

a time-cycle controller with which to establish a control signal outputat predetermined intervals,

a control system between the pressure detector and the basic sedimentand water detector-controller and time-cycle controller and thecompressor and the first and second valves,

whereby the compressor is started and the valves are opened when thepressure of the vapors exceeds a predetermined value and when the basicsediment and Water exceeds a predetermined value and when the time-cyclecontroller establishes its output control signal,

a conduit connected to the compressor output with which the vapor andoil of the compressor output is mixed with the crude petroleum receivedby the means employing heat,

and a measuring means connected to the lower portion of the collectingvessel receiving the clean oil and measuring and transferring the cleanoil to a point of use.

7. A system for treating and transferring crude petroleum, including,

means employing heat to reduce crude petroleum produced from an oil wellinto clean oil and water,

a collecting vessel connected to the means employing heat to receive theclean oil,

a compressor connected to the upper portion of the collecting vessel toremove vapors evolved from the surface of the clean oil and employ cleanoil cooler than the vapors to condense and absorb and compress thevapors,

a first valve in the connection between the upper portion of thecollecting vessel and the compressor,

a second valve arranged to control the cool oil to the compressor,

means-for detecting the pressure of the vapors in the upper portion ofthe collecting vessel,

a detector-controller connected'tothe lower portion of the collectingvessel and responding to the percent basic sediment and water in the oilreceived into the vessel,

a control system between the pressure detector and the basic sedimentand water detector-controller and the compressor and the first andsecond valves,

whereby the compressor is started and the valves are opened whentherpressure of the vapors exceeds a predetermined value and when thebasic sediment and water exceeds a predetermined value,

a conduit connected to the compressor output with which the vapor andoil of the compressor output is mixed with the crude petroleum receivedby the means employing heat,

and a measuring means connected to the lower portion of the collectingvessel receiving the clean oil and measuring and transferring the cleanoil to a point of use.

8. A system for treating and transferring crude petroleum, including,

means employing heat to reduce crude petroleum produced from an oil wellinto clean oil and water,

a lease valve betweenthe means employing heat and the well which can beclosed to shut down the lease,

a collecting vessel connected to the means employing heat to receive theclean oil,

means for detecting a predetermined upper liquid level in the collectingvessel and closing the lease valve when the upper liquid level isdetected,

a compressor connected to the upper portion of the collecting vessel toremove vapors evolved from the surface of the clean oil and employ cleanoil cooler than the vapors to condense and absorb and compress thevapors,

a first valve in the connection between the upper portion of thecollecting vessel and the compressor,

a second valve arranged to control the cool oil to the compressor,

means for detecting the pressure of the vapors in the upper portion ofthe collecting vessel,

a control system between the pressure detector and the compressor andthe first and second valves, whereby the compressor is started .and thevalves are opened when the pressure of the vapors excwds a predeterminedvalue,

a conduit connected to the compressor output with which the vapor andoil of the compressor output is mixed with the crude petroleum receivedby the means employing heat,

a dump-type measuring means connected to the lower portion of thecollecting vessel receiving the clean oil and measuring and transferringthe clean oil to a point of use,

a third valve in the connection between the dump-type measuring meansand the lower portion of the collecting vessel which can be closed toterminate the measuring and transferring of the clean oil,

and means for detecting a predetermined lower liquid level in thecollecting vessel and closing the third valve when the lower liquidlevel is detected as an indication that the collecting vessel does notcontain sufiicient oil to fill the dump-type measuring means.

9. A system for treating and transferring crude petroleum, including,

a supply of crude petroleum,

a container connected to the supply in which the crude is received,

a heat means mounted in the shell of the container and raising thetemperature of the crude until any emulsion of oil and water in thecrude is broken,

.a collecting vessel connected to the shell of the con- 15 tainer andreceiving the clean oil produced from the shell,

a compressor employing a liquid cooler than vapor with which itcondenses and absorbs and compresses the vapor,

a connection removing vapor from the vapor space of the collectingvessel to the input of the compressor,

a source of liquid which is at a temperature less than the vaporsevolved from the surface of the clean oil in the collecting vesselconnected to the compressor,

a conduit connected to the compressor output through which the mixtureof condensate and vapors is removed from the output and returned to thecont ainer connected to the supply of crude petroleum, and measuringmeans connected to the collecting vessel to receive clean oil from thecollecting vessel and measure and transfer the clean oil to a point ofuse.

,10. A system for treating and transferring crude petroleum, including,

a supply of crude petroleum,

a container connected to the supply in which the crude is received,

a heat means mounted in the shell of the container and raising thetemperature of the crude until any emulsion of oil and water in thecrude is broken,

a collecting vessel connected to the shell of the container andreceiving the clean oil produced from the shell,

a heat exchanger mounted within the vapor space of the collecting vesseland circulating a fluid cooler than'vapors evolved from the clean oil inindirect heat exchange with the vapors to reduce the temperature ofevolved vapors until hydrocarbons in it; the vapors which can he held asa liquid under storageable conditions are liquified,

a compressor employing a liquid cooler than vapor with which itcondenses and absorbs and compresses the vapor,

a connection removing vapor from the vapor space of the collectingvessel to the input of the compressor,

a source of liquid which is at a temperature less than the vaporsevolved from the surface of the clean oil in the collecting vesselconnected to the compressor,

a conduit connected to the compressor output through which the mixtureof condensate and vapors is removed from the output and returned to thecontainer to the supply of crude petroleum,

and measuring means connected to the collecting vessel to receive cleanoil from the collecting vessel and measure and transfer the clean oil to-a point of use.

References Cited in the file of this patent UNITED STATES PATENTS2,420,115 Walker et al May 6, 1947 2,457,959 Walker Jan. 4, 19492,528,032 Candler et a1. Oct. 31, 1950 2,765,917 Francis Oct. 9, 19562,773,556 Meyers et al. Dec. 11, 1956 2,808,123 Walker Oct. 1, 19572,860,660 Swatsworth Nov. 18, 1958 2,882,995 Smith Apr. 21, 19592,947,379 Aubrey Aug. 2, 1960 3,021,709 Walker et a1 Feb. 20', 19623,040,572 Henderson et al. June 26, 1962 3,043,072 Walker et a] July 10,1962

1. THE METHOD OF TREATING AND TRANSFERRING CRUDE PETROLEUM INCLUDING.HEATING THE CRUDE TO BREAK ANY EMULSION OF OIL AND WATER IN THE CRUDE,REMOVING AND COLLECTING CLEAN OIL REMOTE FROM THE HEATING STEP,MEASURING THE COLLECTED CLEAN OIL AND DELIVERING THE CLEAN OIL TO APOINT OF USE, REMOVING VAPOR EVOLVED FROM THE CLEAN OIL COLLECTED,